Test: Properties of Metals, Simple Stress Strain & Elastic Constants - 2 - Civil Engineering (CE) MCQ

• Definition: St. Venant's principle states that stress conditions approach uniformly as the distance from the point of application of the load increases.


• Uniform Stress Distribution: This principle implies that within a certain distance from the applied load, the stress distribution in a material will be uniform.


• Equal Stress: The principle also suggests that as the distance from the load increases, the deformations of all materials for a given loading become equal.


• Relieving Stresses: Contrary to option D, St. Venant's principle does not imply that stresses in a loaded member tend to relieve after a point of time. Instead, it focuses on the uniformity of stress distribution.


• Application: Engineers often use St. Venant's principle to simplify stress analysis in structural mechanics, allowing for easier calculations and predictions of material behavior under loads.

Notched bar test- Impact Strength of a Material
Indentation Test- Hardness of a Material
The machinability rating is determined by measuring the weighted averages of the normal cutting speed, surface finish, and tool life for each material.
Salt Spray/Fog Test- Corrosion resistance of the material.

• Creep Test: The creep test is a type of test used to measure the behavior of materials under a constant load over an extended period of time.


• Type of Stress: In the creep test, uniaxial tension stress is applied to the specimen.


• Uniaxial Tension: Uniaxial tension stress refers to the stress applied in a single direction, causing the specimen to elongate.


• Behavior of Materials: By subjecting the specimen to uniaxial tension stress in the creep test, researchers can observe how the material deforms over time and analyze its creep behavior.


• Creep Behavior: Creep behavior is the tendency of a material to deform slowly under a constant load, which is important to understand in various engineering applications.

Since the bar is free to expand, no stresses will be developed in the bar.

• Explanation of Cup-and-Cone Fracture: Cup-and-cone fracture is a type of fracture that occurs in ductile materials when subjected to tensile stress.


• Characteristics of Cup-and-Cone Fracture: This type of fracture is characterized by the formation of a cup-shaped cavity on one side of the fracture surface and a cone-shaped projection on the other side.


• Reason for Occurrence: Cup-and-cone type fracture occurs in round specimens of ductile metals because the stress distribution is symmetrical around the circumference of the specimen.


• Explanation of Other Options:
  
  
  
  • Cast iron typically exhibits a brittle fracture.
  
  
  • Tough steel is more likely to exhibit a ductile fracture rather than a cup-and-cone fracture.
  
  
  • Soft brass is also more likely to exhibit a ductile fracture rather than a cup-and-cone fracture.
  
  
  
  

• Definition of Brittle Materials: Materials with elongation less than 5% are considered brittle.


• Factor of Safety: In the case of brittle materials, the factor of safety is based on the limit of proportionality.


• Explanation: The limit of proportionality is the point on a stress-strain curve where the linear relationship between stress and strain ends. It is the maximum stress at which stress is directly proportional to strain.


• Importance of Limit of Proportionality: For brittle materials, the limit of proportionality is crucial because it indicates the stress level at which the material will no longer behave elastically.


• Design Considerations: When designing structures or components using brittle materials, it is essential to consider the limit of proportionality to ensure that the material does not fail prematurely.

 = 0.4664 x 10⁵ MPa